The GHD back extension is dissimilar in action to CrossFit’s nine foundational movements. The spine actively and deliberately flexes and extends. While you would not want to flex and extend the spine in such a way while lifting, it is important to develop the strength and positional awareness to move from these positions to a neutral position.

There is an adjunct movement to GHD sit-ups in which the athlete is dynamic in the trunk and static in the hip. It is the AbMat sit-up, where we deliberately take the hip flexors out of the equation and work the torso dynamically. The two sit-ups, GHD and AbMat, complement each other beautifully. One is dynamic in the hips and static in the trunk; the other is dynamic in the trunk and static in the hip. In conjunction with the L-sit (static in the trunk and hip), they develop a formidable capacity in the midline.